1. Field of the Invention
The present invention relates to a spinner apparatus with chemical supply nozzles and methods of forming patterns and performing etching using the same.
2. Description of the Related Art
In general, during processes for manufacturing semiconductor devices, electronic circuits are realized by performing certain functions by manipulating and controlling the order in which conductive layers, semiconductor layers, and insulating layers are stacked in combination with the shapes of patterns. In particular, in a semiconductor memory device and a semiconductor logic device, a plurality of unit chips having the same function and shape are repeatedly realized on the semiconductor wafer using a photomask designed for a certain purpose. Also, in the associated unit chips, a plurality of unit cells having the same shape are repeatedly formed in the unit chips in the form of a matrix.
As the semiconductor memory device and the semiconductor logic device become more highly integrated, the sizes of various patterns which constitute each device become even smaller. Accordingly, design rules are reduced to 0.35 xcexcm, 0.25 xcexcm, 0.18 xcexcm, and 0.15 xcexcm. However, contrary to the tendency of device patterns becoming smaller, the sizes of the semiconductor wafers are increasing to 6xe2x80x3, 8xe2x80x3, and 12xe2x80x3 to improve productivity. Correspondingly, sizes of photomasks are increasing to sizes such as 5xe2x80x3xc3x975xe2x80x3, 6xe2x80x3xc3x976xe2x80x3, and 9xe2x80x3xc3x979xe2x80x3.
Therefore, in spite of the sizes of the device patterns being smaller, the sizes of substrates such as the semiconductor wafers or the photomasks are increasing. Accordingly, it is more difficult and important to form and manage the critical dimensions of the device patterns which are identically and repeatedly formed in the enlarged semiconductor wafer or photomask to be uniform all over the substrate. In particular, in the case of the photomask, it is more important to manage the uniformity of the critical dimension since the photomask operates as a disc for transcribing the image of the pattern formed on the photomask into the wafer.
FIG. 1 schematically shows the position of a spray-type nozzle 12, 14 on the photomask 10 in a conventional photomask apparatus, in which steps of a developing process for forming the pattern on a photomask 10 are shown. Referring to FIG. 1, the photomask 10 is divided into a binary mask for controlling the intensity of light and a phase shift mask for simultaneously controlling the phase and intensity of light. Hereinafter, the binary mask will be described.
A schematic square blank substrate, in which a light shielding film 10b is formed on a substrate 10a, is provided. High purity synthetic quartz glass having characteristics of high light transmissivity and low thermal expansion is generally used as the substrate 10a. A multi-layer structure of metal chrome and chrome compound is generally used as the light shielding film 10b. 
The light shielding film 10b is coated with a resist layer 10c. In a positive-type E-beam resist, an electron beam decomposition type resist in which an organic solvent is used as a developing solution is mainly used as the resist layer 10c. In a negative-type E-beam resist, a chemical amplified resist (CAR) is used as the resist layer 10c. 
An exposing process is performed on the resist layer 10c using an exposure apparatus according to the designed pattern. A raster scan type apparatus and a vector scan apparatus in which a spot beam is used are commonly used as the exposure apparatus. An exposing apparatus using a multi-beam is typically used. In FIG. 1, reference numeral 10cxe2x80x2 denotes the exposure region of the resist layer which is exposed to light and creates a chemical reaction.
A designed resist pattern is formed by developing and removing the exposure region 10cxe2x80x2 of the resist layer using the developing solution. Then, an etching process is performed on the light shielding film 10b using the resist pattern as the etching mask and a remaining resist pattern material is removed. Accordingly, a predetermined light shielding film pattern is formed on the substrate 10a. Therefore, a desired photomask is manufactured.
In the processes of manufacturing the photomask, the exposing process and the developing process are most important in determining the CD uniformity of the mask. In the exposing process, the uniformity of the CD is dependent on the reproducibility of pparatuses when a writing method, a substrate, and an accelerating voltage are determined in the exposing apparatus. Meanwhile, in the developing process, the uniformity of the CD can vary according to a developing apparatus and a developing method.
FIG. 1 shows one conventional process of manufacturing the photomask. In the developing process, the developing solution is supplied to the photomask 10 on which the exposing process is performed, thus developing the exposure region 10cxe2x80x2. The developed exposure region 10cxe2x80x2 is then removed. The developing solution is sprayed by a first spray-type nozzle 12 and a second spray-type nozzle 14. At this time, the photomask 10 is fixed horizontally to the fixing chuck (not shown) of a rotating spinner and rotates at a certain speed. FIG. 2 is a plan view of FIG. 1, which shows the positions of the first spray-type nozzle 12 and the second spray-type nozzle 14 which are positioned on the photomask 10.
According to the conventional spin spray developing process, the resist pattern formed on the square photomask 10 rapidly changes in a concentric circle direction from the rotation center of the spinner. This is because various processing conditions in the rotation center do not coincide with those in the rotation edge since the photomask rotates in a state of being fixed to the fixing chuck of the spinner and the developing process is performed using fluid chemicals. Therefore, research on methods for improving the uniformity of the CD by maintaining the processing conditions all over the substrate such as the photomask and the wafer have been continuously required.
Results of comparing various methods of the developing process which greatly affect the uniformity of the CD are disclosed in xe2x80x9cStudy of Development Methods For Chemical Amplification Resistxe2x80x9d Hidetaka Saito, et al, SPIE Vol. 3412, pp. 269-278, 1998. According to this article, when the deviation of the CD is measured after performing the developing process by a conventional shower-spray development method, a puddle development method, and a dip development method, the deviation of the CD (3xcex4) is 17 nm, in the case of the dip development method. However, in the case of the dip development method, the developing solution must be renewed at all times in order to maintain a low level of defects in the mask. Accordingly, a large amount of developing solution is necessary, which is not economical. Therefore, a soft-shower development method in which the spray pressure of the developing solution is changed is disclosed the above article. However, problems of the developing process of the conventional spin-spray method are not completely solved since processing conditions in the center of the substrate, i.e., the center of the rotation, are different from those at the edge of the substrate, which is significantly affected by the centrifugal force caused by the rotation.
To solve the above problem, it is an object of the present invention to provide a spinner apparatus with chemical supply nozzles capable of improving the critical dimension uniformity of a pattern formed on a substrate during a developing process or an etching process, which is performed by a spin method using chemicals.
It is another object of the present invention to provide a method for forming a pattern, capable of improving the critical dimension uniformity of the pattern formed on the substrate during the developing process performed by the spin method using chemicals.
It is another object of the present invention to provide an etching method capable of improving the critical dimension uniformity of an underlayer pattern etched using the pattern which was previously formed on a specific underlayer on the substrate as an etching mask, during an etching process performed by the spin method using chemicals.
The above objects are achieved by providing a plurality of supply nozzles for supplying a developing solution or an etching solution and independently controlling processing conditions such as the temperature of chemicals supplied from the plurality of supply nozzles when manufacturing a photomask, developing a resist pattern on a specific substrate, or etching using the resist pattern as an etching mask.
In accordance with one aspect of the invention, there is provided a spinner apparatus including a rotating member or platform to which a substrate is fix horizontally. A plurality of chemical supply nozzles separated from each other by a predetermined distance are provided for vertically and downwardly supplying process performing chemicals to the substrate. A chemical supply source stores the chemicals supplied to the chemical supply nozzles, and a plurality of chemical supply pipes are provided between the chemical supply source and the chemical supply nozzles.
In one embodiment, the temperature of the chemicals supplied to the substrate through the chemical supply nozzles is independently controlled in each supply nozzle. In addition, the flux of the chemicals supplied to the substrate through the chemical supply nozzles is independently controlled in each supply nozzle. Also, the chemical supply nozzles can be stream-type nozzles which vertically and downwardly flow the chemicals. The chemical supply nozzles can vertically and horizontally move with respect to the substrate.
The process performing substrate can be a photomask, a semiconductor wafer, a liquid crystal display (LCD) substrate, or a flat panel display (FPD) substrate. The spinner apparatus can be a developing apparatus or an etching apparatus.
In accordance with another aspect of the invention, there is provided a method for forming a pattern. An etched material layer to be etched and a pattern forming material layer are sequentially formed on a substrate. An exposing process is performed to define a pattern on the pattern forming material layer. The substrate is loaded on a rotating member or platform in a processing chamber in which a processing temperature is controlled. A plurality of supply nozzles are provided at a plurality of positions above the substrate, each of the supply nozzles providing a developing solution, the temperature of which is independently controlled. At least part of the pattern forming material layer on which the exposing process is performed is developed and removed by rotating the substrate and vertically and downwardly flowing the developing solution from the plurality of supply nozzles above the substrate.
In order to optimize processing conditions, a critical dimension (CD) can be measured in each position on the substrate with respect to the pattern formed by removing part of the pattern forming material layer, and the temperature of the developing solution supplied from each position above the substrate can be controlled on the basis of the measured CDs of each position.
In accordance with another aspect of the invention, there is provided a method for performing etching. An etching mask layer is formed having a specific pattern on a substrate on which an etched material layer is formed. The substrate on which the etching mask layer is formed is loaded on a rotating member or platform in a processing chamber in which a processing temperature is controlled. At least part of the etched material layer is etched and removed by rotating the substrate and vertically and downwardly flowing an etching solution from a plurality of supply nozzles above the substrate, the temperature of the etching solution from each nozzle being independently controlled.
In order to optimize processing conditions, a critical dimension (CD) in each position on the substrate can be measured with respect to the pattern of the etched material layer, and the temperature of the etching solution supplied from above the substrate to each position can be controlled on the basis of the measured CD.
According to the present invention, the deviation of the CD is very small all over the mask or the substrate since the temperatures and fluxes of the chemicals, which are supplied from a plurality of chemical supply nozzles which are separated from each other on the photomask or the substrate, are independently controlled. According to the present invention, the deviation of the CD all over the substrate is reduced by independently managing the plurality of chemical supply nozzles.